The present invention relates to a sole for a shoe, in particular for a sports shoe.
When shoes, in particular sports shoes, are manufactured, the design of the sole has a particular importance. This part not only determines the grip of the shoe on the ground but also controls by its deformability the stress on the muscles and the joints of the wearer of the shoe arising during a step cycle. Further, it influences the energy necessary for running.
Accordingly, it has for many years been the objective of the development of sports shoes to optimize the properties of shoe soles under stress. When in the following the term xe2x80x9csports shoexe2x80x9d is used, this refers to shoes for all kinds of sports, for example jogging shoes, sprint shoes, soccer shoes, but also hiking boots etc.
The properties of a shoe sole under stress canxe2x80x94as the shock absorber of a vehiclexe2x80x94essentially be described by the two terms elasticity and damping. The elastic components of a system are reversibly deformed by an external force and release, when the external force is removed, essentially without any loss the energy stored in the deformation. Damping, however, is called a deformation which is essentially irreversibly transformed into heat and which can therefore not be regained by the system.
As in the case of a shock absorber of a vehicle, it is also in the construction of shoe soles decisive to balance these two aspects in view of the intended use of the shoe, i.e. to either design the sole more elasticallyxe2x80x94for example for sprint shoesxe2x80x94or to focus on the damping of the shoe for a greater comfort or protection of the joints of the wearer.
In sports shoes according to the prior art the desired balancing was to be achieved by a suitable selection of the material, in particular of the intermediate sole or midsole, i.e. a single element, usually consisting of a foamed material (EVA) with elastical as well as damping properties. However, it was found that soles of this type change due to the constant stress during their lifetime their properties and that in particular the elasticity of the foamed to material significantly decreases. As a result, the shoe becomes too soft, so that the energy needed for one step cycle significantly increases. Further, a too soft shoe is unstable so that the danger of an overpronation arises, i.e. the excessive rolling of the foot to the medial (inner) side or an oversupination, i.e. the excessive rolling to the lateral (outer side) during a step. Since a separate replacement of the midsole is not possible, the complete shoe has to be replaced in such a case.
From the U.S. Pat. No. 5,799,417 a sole construction is known where a movable part of the outsole is provided allowing the replacement or the mounting of different midsole elements in the heel part of the shoe. The movable part of the outsole comprises like a cage the midsole element from all sides and assures thus the mounting to the shoe. However, also in this case damping and elasticity of the shoe sole are combined in a single component, the midsole element, so that a separate adjustment of one of the two aspects is not possible.
It is therefore the problem of the present invention to provide a sole of a shoe, in particular a sports shoe, where the elasticity and the damping of the sole can be independently of each other determined.
The present invention relates to a sole for a shoe, in particular a sports shoe, with a support plate, at least one damping element arranged below the support plate and at least one spring element mounted to the support plate, where the spring element is essentially L-shaped and thereby encompasses the damping element from the side and from below.
Since the at least one damping element is encompassed by the L-shaped spring element, a deflection of the spring element leads to a simultaneous compression of the damping element. Although both elements are therefore together deformed during ground contact of the sole, the design of the spring element determines the elasticity of the sole, whereas the damping properties are independently determined by the at least one damping element.
According to a preferred embodiment, the damping element and the spring element are releasably mounted to the support plate. This allows on the one hand that both elements can be replaced after prolonged use. On the other hand, the shoe may easily be adapted to different fields of use by different damping and/or spring elements.
Preferably, at least one medial and one lateral damping element are provided to account for different stress on these parts of the sole. For the elasticity this is reflected by the fact that preferably a medial and a lateral spring element are provided. An overpronation or oversupination can therefore be independently of each other avoided.
Preferably, the lateral as well as the medial damping element are encompassed by several medial or lateral spring elements, respectively. Thus, a reliable anchoring to the support plate is provided. The spring elements are preferably mounted to the outer edge of the support plate and extend inwardly. With this orientation, the sole is even with soft damping elements particularly stable in the boarder area to avoid a pronation or supination. On the lower side of the spring elements, contacting directly the ground, additional friction feet are preferably provided to assure a good grip of the sole according to the invention.
Further advantageous developments of the sole according to the invention are subject matter of the dependent claims.